Amid the rash of appeals for Haiti donations has come a call from one of the most prominent voices on the American right for people to hang on to their cash because Barack Obama might steal it.

Rush Limbaugh, the most popular radio talkshow host, who is sometimes described as the real leader of the Republican party, says Americans should not give a penny to a population struggling for survival after the earthquake.

Limbaugh agreed with a caller suspicious that the White House website was being used to direct funds to the American Red Cross. "Would you trust the money's gonna go to Haiti?" the caller asked. Limbaugh then said Obama was exploiting the disaster for political ends.

"This [the earthquake] will play right into Obama's hands," said Limbaugh. "He's humanitarian, compassionate. They'll use this to burnish their, shall we say, credibility with the black community – both light-skinned and dark-skinned black community in this country. This is made to order for them."

Limbaugh also warned Americans against donating money. "Besides, we've already donated to Haiti. It's called the US income tax," he said.

The movie critic Roger Ebert responded with an open letter to Limbaugh: "Tens of thousands are believed still alive beneath the rubble. You twisted their suffering into an opportunity to demean the character of the president."

The evangelical leader Pat Robertson has also drawn criticism for suggesting Haiti had brought decades of torment on itself by making a pact with the devil to end French rule. The White House press secretary, Robert Gibbs, described Robertson's remarks as "utterly stupid".

He also condemned Limbaugh: "I think to use the power of your pulpit to try to convince those not to help their brothers and sisters is sad," he said.

Crass remarks were not restricted to rightwing Americans. A senior Haitian diplomat was caught on camera claiming the earthquake would be good for his country and appearing to blame the catastrophe on "witchcraft".

Speaking before an interview on Brazilian TV, Haiti's consul in São Paulo, George Samuel Antoine, said: "This catastrophe is good for us here, it will make us known."